[PATCH] time: verify time values in adjtimex ADJ_SETOFFSET to avoid overflow

[Sasha Levin]

Make sure the tv_usec makes sense. We might multiply them later which can
cause an overflow and undefined behavior.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
 kernel/time/timekeeping.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index d563c19..aa3c1c2 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1987,6 +1987,10 @@ int do_adjtimex(struct timex *txc)
 
 	if (txc->modes & ADJ_SETOFFSET) {
 		struct timespec delta;
+
+		if (txc->time.tv_usec >= USEC_PER_SEC || txc->time.tv_usec <= -USEC_PER_SEC)
+			return -EINVAL;
+
 		delta.tv_sec  = txc->time.tv_sec;
 		delta.tv_nsec = txc->time.tv_usec;
 		if (!(txc->modes & ADJ_NANO))
-- 
1.7.10.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/